1. Field of The Invention
The present invention relates generally to an odor sensing system having high recognitivity. Specifically, the present invention relates to an odor sensing system having high recognitivity which can discriminate closely parallel odors.
2. Description of The Background Art
Generally, human sensory tests have been applied for controlling quality of various substances such as food products, drinking products and cosmetics by discriminating odors thereof. Alternatively, human sensory tests have been applied for estimation in environmental and clinical fields. However, human olfaction is varied readily, because it depends on bodily or ambient conditions of the tester. Therefore, in order to obtain objective results constantly, odor sensing systems replacable with human olfaction have been developed.
Commonly, gas sensing systems as such odor sensing systems are well known in the art. For example, Japanese Patent First Publication (not allowed) No. 1-244335 discloses a gas sensing system which imitates human olfaction, i.e., a plurality of gas sensors are employed to receive odor stimulation, then pattern recognition is done. In human olfaction, a variety of odor stimulating patterns are received by a plurality of receptors, then the output patterns from the receptors are recognized in olfactory neural network system to discriminate odors. The aforementioned prior art replaces the receptor by a quartz resonator sensor, and replaces an olfactory neural network system by an artificial neural network system. Odors are discriminated by recognition of a variety of patterns output from a plurality of resonators via a neural network system.
However, many odors which are required to be discriminated are extremely proximate each other, so the sensing system as aforementioned cannot sufficiently distinguish various odors.
Additionally, homogeneity of a supplied sample is apt to fluctuate in the plurality of sensors. Therefore, different results are obtained frequently, even if the same odor is provided to the sensory test.